For the cake:
- 6 massive egg whites
- 1 cup (2 sticks) unsalted butter, softened
- 2 ¼ cups granulated sugar (424 g)
- 2 teaspoons vanilla extract
- 1 cup mild sour cream
- ½ cup milk
- 2 ¾ c flour (340 g)
- 1 teaspoons seat salt
- 1 teaspoon baking soda
For the blueberry syrup:
- 12oz (340g) blueberries
- 1 cup granulated sugar
- 1 cup water
- For the frosting:
- 2 cups (four sticks) unsalted butter, softened
- 8 cups powdered sugar
- 2 tablespoons heavy whipping cream
- Prepared blueberry sauce
For the topping:
- 1 cup white chocolate chips
- 3/4 to one cup heavy whipping cream
- ¼ cup pistachios for garnish
For the cake:
- Preheat the oven to 350°F. Grease 3 8-inch pans and line with parchment paper.
- Using the steel bowl of your stand mixer with the whisk attachment, whisk the egg whites on medium-high velocity until stiff peaks shape. Remove whipped eggs whites from the bowl and set aside.
- Change to the paddle attachment and integrate unsalted butter, granulated sugar and vanilla extract. Cream together for 2-3 minutes until well combined.
- Add the bitter cream and milk to the combination bowl and beat at a low pace till all components are properly combined, scraping down the bowl as needed.
- In a separate bowl, combine the flour, salt and baking soda and stir to combine.
- With the mixer on a low pace, slowly add the flour mixture to the bowl and continue mixing till combined, scraping down the bowl as wished.
- Using a spatula, fold the egg whites into the batter, turning the batter over lightly until the egg white are properly mixed. This may additionally take a little elbow grease, however do now not mix vigorously or you will deflate the egg whites.
- Divide the batter evenly between the 3 cake pans. Bake at 350°F for 18-22 mins, rotating the cakes inside the oven halfway through to ensure even baking. To test for doneness, insert a toothpick into the middle of the cake. If the toothpick comes out smooth, your cake is carried out. Allow the cake to cool completely.
For the blueberry sauce:
- Start with the blueberry syrup. In a medium saucepan, integrate blueberries, granulated sugar and water. Simmer over medium warmth till the sauce is decreased by way of half of, this must take approximately 20 minutes. Sauce will thicken as it reduces.
- Strain the sauce thru a excellent sieve, the usage of a spatula to push the sauce through the sieve. Place the juice inside the fridge till it’s completely cool.
- For the frosting: Cut the butter into portions. Using the paddle attachment, whip the butter for three-four minutes, scraping down the bowl occasionally. Beat until the butter seems light in coloration.
- Add four cups of powdered sugar, one cup at a time and mix on low velocity till it’s included into butter. The frosting will begin to thicken.
- Begin to exchange within the blueberry sauce and heavy whipping cream whilst alternating in additional cups of powdered sugar until all the powdered sugar, heavy cream and blueberry sauce have been introduced. Continue beating until all substances are combined after which beat it at a high velocity for 1 minute to whip some additional air into the frosting.
- To build the cake: Even out the pinnacle of the cake with the aid of slicing off the dome using a serrated knife.
- Place a dollop of frosting on the lowest of the cake plate and location the lowest layer of cake on pinnacle. The frosting will assist prevent the cake from sliding.
- In order to create even layers, I use a piping bag equipped with an open round tip, or simply cut off the cease of the piping bag. I also noticeably recommend the usage of a lazy Suzan to rotate the cake as you figure.
- Fill the first layer of frosting with the aid of the usage of your piping bag and pipe from the outdoor edge into the center. Gently unfold the frosting with an offset spatula to fill inside the gaps.
- Place the next layer of cake on pinnacle and repeat the above instructions to fill the layer of frosting.
- For the pinnacle layer of cake, location it inverted, so the bottom of the cake is certainly the top, growing a nice and smooth pinnacle facet.
- Proceed to add your crumb coat by using including a cup of frosting to the top of the cake and gently unfold out to the rims and down the sides. Use the leftover frosting to your piping baggage to fill inside the cracks between the layers.
- Using an offset spatula or icing smoother, wipe away the extra frosting, leaving you simply sufficient to coat the out of doors of the cake. Do not mix your crumb coating frosting returned into your icing if it has cake debris in it. Refrigerate the cake for 15-20 mins to allow the crumb coat to harden.
- Remove the cake from the fridge and continue to feature the closing frosting to the pinnacle and edges of the cake. To get a pleasant clean side, use your offset spatula and icing smoother to wipe away extra frosting.
- Take the extra frosting and pipe florets on top of the cake.
For the ganache:
- In a microwave-secure bowl, combine the white chocolate and heavy whipping cream. Microwave at 50 percentage electricity for 30 seconds at a time, and stir after each 30 seconds. Repeat till the chocolate is melted and smooth. The white chocolate ganache must run smoothly off your spoon. Add extra heavy whipping cream if needed to make the ganache thinner.
- Drizzle the white chocolate down the perimeters and over the top of the cake.
- Garnish with overwhelmed pistachios.